PTGER1 and neoplasm: This study has two primary objectives: to evaluate PTGER1 as a diagnostic and prognostic biomarker across multiple cancer types, and to investigate its role in immune modulation and genetic variation. Utilizing publicly available datasets, including Gene Expression Profiling Interactive Analysis (GEPIA), the University of ALabama at Birmingham CANcer Data Analysis Portal (UALCAN), and the Tumor Immune Estimation Resource (TIMER), we systematically analyzed gene expression profiles, immune cell infiltration, survival outcomes, and prevalent genetic alterations.